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4. Troubleshooting
4-1-4. ADDITIONAL BACKLIGHT
<LD Board>
•
If BACKLIGHTS ON BUT A PANEL SECTION(S) OFF
Each Supply Drive (
9
All should measure the same.
-
If a Supply Drive measures low or no voltage:
•
Disconnect AC power then remove the related panel connector.
•
Reconnect AC power.
Measure defective voltage again.
9
-
If it stays low the
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If it goes high the
-
If all Supply Drive Voltages measures OK:
Measure each diode CH1 thru CH24 anode side (Non stripped side) for approx
9
-
If a voltage is very low (about 1 volt) the
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If a voltage is high (near Drive Voltage) the
BACKLIGHT DIMMING PROBLEMS ON FULL SCREEN OR JUST ONE ARE
•
Go to
Menu £ Picture £ Backlight and vary level (0 – 20)
•
If no backlight changes are observed problem is Main Board or LD Board.
Anode side (no stripe) of CH1 thru CH 24 Diodes for voltage change while changing backlight level.
9
(Approx. 45Vdc at 0 level to 38Vdc at 20 level)
If no voltage changes
9
•
If voltage changes in all diodes except the one with area problem replace
4-6
75Vdc) at Ch1 thru Ch24 at each Diode (cathode stripped side) locations.
SMPS is defective.
Panel is defective.
Main Board is likely defective.
Panel is defective.
LD Board is defective.
38Vdc.
LD Board.
75Vdc
38Vdc
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